Evaporative cooler

ABSTRACT

THIS DISCLOSURE RELATES TO A ROOF TOP EVAPORATIVE COOLER FOR COOLING THE INTERIOR OF VEHICLES SUCH AS CAMPERS AND TRAILERS, WHETHER THE VEHICLE IS MOVING OR STATIONARY. THE UNIT INCLUDES A REAR FACING STREAMLINED HOUSING DISPOSED OVER A ROOF TOP REGISTER, WITH A WIND DEFLECTOR SUCH AS A SPOILER FOR DIRECTING THE AIR STREAM PASSING OVER THE UNIT INTO A LOUVERED ENTRANCE PORT. A SUCTION FAN IS DISPOSED WITHIN THE HOUSING BETWEEN THE ENTRANCE PORT AND THE REGISTER FOR PULLING AIR INTO THE HOUSING, THROUGH AN EVAPORATIVE PAD AND FOR EXPELLING THE COOLED AIR, GUIDED BY THE CONFIGURATION OF THE HOUSING, THROUGH THE REGISTER AND INTO THE VEHICLE. THE COOLING MEDIUM IS PUMPED FROM A SUPPLY TANK TO A DISTRIBUTOR OVER THE PAD AND COLLECTED AFTER IT PASSES THROUGH THE PAD FOR RECIRCULATION. THE SUPPLY TANK MAY BE EITHER INCORPORATED WITHIN THE COOLER HOUSING OR EXTERNALLY DISPOSED THERETO AND MOUNTED ON THE VEHICLE BODY. THE PAD IS CONSTRUCTED FROM A SUITABLE POROUS MATERIAL AND THE COOLING MEDIUM IS TYPICALLY WATER.

Se t. 21, 1971 L. ANDERSQN EVAPORATIVE COOLER Filed Nov. 10. 1969INVENTOR LES ANDERSON ATTORNEYS United States Patent 3,606,982EVAPORATIVE COOLER Les Anderson, Las Vegas, Nev., assignor to Everkool,Inc., Las Vegas, Nev. Filed Nov. 10, 1969, Ser. No. 875,084 Int. Cl.B0lt 3/04 US. Cl. 261-29 13 Claims ABSTRACT OF THE DISCLOSURE Thisdisclosure relates to a roof top evaporative cooler for cooling theinterior of vehicles such as campers and trailers, whether the vehicleis moving or stationary. The unit includes a rear facing streamlinedhousing disposed over a roof top register, with a wind deflector such asa spoiler for directing the air stream passing over the unit into alouvered entrance port. A suction fan is disposed within the housingbetween the entrance port and the register for pulling air into thehousing, through an evaporative pad and for expelling the cooled air,guided by the configuration of the housing, through the register andinto the vehicle. The cooling medium is pumped from a supply tank to adistributor over the pad and collected after it passes through the padfor recirculation. The supply tank may be either incorporated within thecooler housing or externally disposed thereto and mounted on the vehiclebody. The pad is constructed from a suitable porous material and thecooling medium is typically water.

Evaporative coolers depend upon the well known principle that as a warmair stream passes in intimate contact with a body of water, heat istransferred from the air to the water, and the water evaporates. Thisprinciple has found a variety of applications in humidifiers and largescale air conditioning units.

Prior small scale adaptations have encountered design difficultiesbecause the unit must provide for passage of a large volume of air inintimate contact with water over a large surface area. However, thismust be accomplished within a small unit for efficient cooling.

Prior interior cooling devices for moving vehicles have utilized anevaporative pad disposed in an air scoop opening in the directionmovement. This device, a. ram-type, only cools when the vehicle ismoving, and has several disadvantages. Insects and debris foul theentrance port reducing the flow of air, and the design inherentlycreates vehicle drag. This drag requires a strong bracing systemconnecting the unit and the vehicle, and the drag causes an increase invehicle gasoline consumption.

Rearwardly opening units have been proposed, but such units have not'been feasible. Although such units could be streamlined, the turbulencecaused by air rushing over the unit resulted in turbulent low pressureat the rear entrance port. In order to pull warm air into the system, alarge suction fan was required. The size of the fan required when thevehicle was moving was grossly disproportionate to the size requiredwhen the vehicle was not moving because in the latter instance there wasno turbulent low pressure at the entrance port. Therefore, these unitswere uneconomical and expensive.

Other rearwardly opening evaporative coolers have been of complicatedconstruction or of limited special utility. One such unit is intended tobe attached to the rear wall of a truck cab for cooling an interiorsleeping area. This device utilizes a falling stream of water against arising current of air which is filtered, cooled, dried and subsequentlyblown into the cab adjacent the sleeping area. Such a device is notadaptable for relatively large vehicles such as campers or trailerssince most efficient cooling requires air injection at the top while the3,606,982 Patented Sept. 21, 1971 ice prior device is attached at therear of the vehicle. The device could not practically be top mountedsince it requires that warm air enter at the side of an elongatedtubular structure and follow an upwardly directed Z- shaped path fromthe warm air inlet to the cool air outlet and into the cab.

As noted above, a universally adaptable cooling unit for relativelylarge vehicles wherein the available space is designed for eitherstorage or living area ideally should be mounted on the roof aspreviously noted. Rear mounting would, in most cases, necessitate aspecial arrangement of living and sleeping quarters to allow forcirculation. Moreover, maximum effective circulation of cool air withoutrearrangement of the existing living and sleeping areas is achieved withan overhead unit.

A rear mounted unit has another disadvantage similar to prior rearopening top mounted units. A large enough fan is required while thevehicle is moving to suck in warm air from the turbulent low pressuretrough following the vehicle. However, when the vehicle is at rest, andthe unit is in use, a smaller fan would be adequate. Therefore the useof the large fan would be unduly expensive if a cooler could be designedto use a smaller fan even when the vehicle is in motion.

The device of the preesnt invention broadly includes a streamlinedhousing with a rearwardly opening louvered entrance port, a verticalevaporative pad fed by recirculating flow of an evaporative coolant suchas water, and a suction fan. The fan sucks air into the housing throughthe entrance port and through the evaporative pad wherein it is cooled.The cooled air stream is then directed downward into the vehicle througha register in the roof of the vehicle, by shape of inner surface of thestreamlined housing. The inner surface of the housing aids the fan byacting as a slightly converging nozzle to further speed the air flowthrough the housing and into the vehicle. Expansion of the air flow asit passes through the register and into the vehicle gives an additionalcooling effect to the flow of air.

Accordingly, it is an object of this invention to provide a rear openingroof top evaporative cooler for vehicles such as campers or housetrailers.

Another object is to provide such a device with a spoiler to direct theflow of air into the cooler and fan to propel the cooled air from thecooler, into the vehicle.

It is another object to provide a roof top cooler which is equallyefficient for moving or parked vehicles.

It is also an object to provide such a device which will exert a minimumdrag on the vehicle when moving and require a relatively small fan foreffective cooling.

It is another object to provide a compact and efficient roof top coolerfor vehicles having a recirculating coolant supply, the cooler beingsmall, streamlined, and effective to cool either a moving or stationaryvehicle.

It is yet another object to provide an evaporative roof top cooler formoving or stationary vehicles using a falling stream of water in aporous pad, the pad being disposed across the stream of warm airentering the cooler, a portion of the falling water evaporating tohumidify and cool the air and the remaining water being collected forrecirculation for additional evaporative cooling.

It is a further object to provide an evaporative cooler wherein warm airis sucked through a moisture laden evaporative pad wherein it is cooled,humidified and directed into the area to be cooled, the pad having arecirculating source of evaporative coolant from a storage area easilyaccessible for refilling.

The exact nature of the invention, as well as other objects andadvantages will become readily apparent with reference to the followingdrawings and description wherein:

FIG. 1 is a perspective view of a vehicle with the FIG. 3 is a crosssectional view of the cooler of FIG. 2

taken along lines 33 of FIG. 2;

FIG. 4 is a side view of the cooler of this invention in partial sectionand showing an alternative coolant storage tank placement and coolantrecovery configuration.

As seen in FIG. 1, the evaporative cooler of this invention 11 ismounted on the roof of a vehicle such as a camper. The cooler 11 iscomprised of an outside housing 12 formed of sheet metal, reinforcedplastic or other suitable material. Housing is formed with a streamlinedleading surface 13 and a rear facing entrance port 15 through which thewarm air is drawn into the device. Disposed above entrance port 15 is awind deflector or spoiler 17 for directing air rushing over the surface13 into the port 15, thereby defeating the formation of a vacuum atentrance port 15. The port 15 may additionally have louvers 18 (see FIG.2) to shelter the interior of the cooler from the weather and insectsand other foreign matter which might be sucked in through the entranceport 15.

Cooled, humidified air from cooler 11 enters the space to be cooledthrough an exhaust port 19. As illustrated in FIG. 2, port 19 includes astepdown deflector 21 extending through a hole 23 in the roof 24 of thevehicle to be cooled. Alternatively, stepdown deflector 21 may bereplaced with a conventional fiat register (not shown) if desired.

Cooler 11 is secured to the roof of the vehicle in any conventionalmanner such as with a roof jack or bracket 25 as shown in FIG. 2,connecting the cooler 11 at the exhaust port 19 with the roof 24 of thevehicle at hole 23. Other means of attachment such as by welding, ordirectly 'with rivets or bolts could also be employed.

As previously noted, cooling is effected by passing a stream of airthrough a moisture laden medium. According to this invention, thismedium is comprised of porous pad 27 disposed within the cooler 11adjacent entrance port 13. The pad 27 may be made of several layers ofcloth, of foam molded plastic, shredded wood fibers retained in an openmesh screen or other suitable material. Preferably, a metal or moldedplastic frame 29 is provided to hold pad 27 and to simplify padreplacement when necessary. This may be done, e.g., by removal of thelouvers 18 thereby providing convenient access to the interior of cooler11 through port 15.

Warm air is sucked into cooler 11 through entrance port 15 and throughpad 27 by fan 31. The fan 31 is surrounded by a shroud 32, and ismounted by bracket 33 to the said shroud as shown in FIG. 2. The fan mayalso be secured to the inner surface of the front portion 13, ifdesired, or it may be mounted at the floor portion 34 of cooler 11 witha suitable bracket. The fan may have either two blades 35 as pictured inFIG. 2, or four, or the fan may be of the squirrel cage type dependingon the volume of air to be moved. The fan blades 35, normally disposedin the same plane as the shroud 32, are preferably driven by a 6 or 12volt electric motor. The fan should be capable of moving between 250 and1000 cubic feet of air per minute (c.f.m.) through the cooler, dependingon the size of the vehicle to be cooled. However, a fan capable ofmoving from 300 to 500 c.f.m. is preferred for most applications. Themotor for such a fan should draw less than 1.0 ampere, e.g., about 0.8ampere for most satisfactory operation.

A coolant 38, such as water, is fed by pump 39 through a pipe 41 to aseepage tube 43 which is disposed over pad 27 as shown in FIGS. 2 and 3.Tube 43 is perforated by holes 45 as shown in FIG. 3 to allow thecoolant to fall on the upper surface of pad 28. The pad is maintained ina saturated condition so that as warm air is drawn through port 15 andpad 27 by fan 31, it will cause 4 the liquid water in the pad 27 toevaporate, cooling and humidifying the air with the vaporized water. Apump, driven by an electric motor which draws about .5 ampere andachieves a flow of 0.5 to 1. 0 gallan per minute should be provided tokeep the pad 27 sufficiently saturated.

As will be understood, a portion of coolant 38 evaporates in the processof cooling the incoming air, but a substantial volume of coolant seepsdown through pad 27, and is caught by a splash pan 47. Fan 47 is formedof plastic or sheet metal and is in the form of an inverted four-sidedpyramid with a drain opening 49 at the lowest point as illustrated inFIGS. 3 and 4. As illustrated in FIG. 2, pan 47 extends the width of pad27.

In an alternative and preferred embodiment, pan 47 extends behind pad 27as shown in FIG. 4 to catch any coolant drawn out of the pad with thecooled air.

In the embodiment of FIG. 4, seepage from outlet 49 in pan 47 falls intoan intermediate storage tank 51, or it may fall directly into the mainstorage tank 53 as in the embodiment of FIG. 2.

In the embodiment of FIG. 4, the main storage tank 55 is disposedexternally to cooler 11 and conventionally mounted on the front or sideof the vehicle as indicated in phantom in FIG. 1. Coolant 38 flows bygravity through pipe 57 from intermediate tank 53 to main tank 55. Tank55 is provided with an accessible filling port 59 and a sight tube 61for convenient gauging of the amount of coolant 38 in the system.

In the embodiment of FIG. 2, tank 53 also is provided with a fillingport and gauge (not shown) which are located in an accessible manner forconvenient use.

During recirculation, pump 39 draws water from main tank 53 or 55through a filter 63 and a line 65 for transmission through line 41 toseepage tube 43. The coolant 38 saturates pad 27, and flows by gravitythrough pad 27 for collection in the splash pan 47 The return flow frompan 47 is directly into storage tank 53 (in the embodiment of FIG. 2) orthrough intermediate tank 51, and thence to the main tank 55 in theembodiment of FIG. 4.

As shown in FIG. 2, a check valve 67 is inserted in line 41 above pump39 to act as a trap for the pump primer if a centrifugal pump is used. Asubmergicle pump can also be used, but this requires that the pump besituated within the storage tank where it is not readily accessible forservicing. Tanks 51, 53 and 55 are preferably completely sealed toprevent spillage when the vehicle is moving and to minimize evaporativewater loss.

It has been found that various engineering changes may be made withinthe scope of this invention, such as varying the type of fan and thetype of pump employed as previously explained. The type of fan and pumpselected will depend upon the volume of air to be cooled which in turnwill depend in part on the size of the vehicle.

The structural design may also be modified according to the nature ofthe vehicle to be cooled. Of the two embodiments, one with the storagetank disposed within the cooler, and the other with the tank external tothe cooler, attached to the vehicle, the former embodiment may bepreferred because as shown in FIG. 2, the cooler is selfcontained andeasily installed. However, the embodiment of FIG. 4 is easily filled andthe sight gauge 61 is conveniently accessible for visual inspection ofthe coolant level, which makes this embodiment advantageous undercertain conditions. In this regard, it should be noted that the coolantlevel should not be permitted to drop to the point of exposing thenormally submerged pump inlet because in the event a centrifugal pump isused, it would have to be primed to restart the cooler.

A practical and commercially satisfactory roof top evaporative coolerfor trailers, campers and other vehicles has herein been described.Broadly described, the cooler operates by drawing arm air into thecooler through a liquid saturated pad, and expelling the evaporationcooled air downward through a register into the vehicle.

A pump draws the liquid coolant from a storage tank and feeds it througha seepage tube over the pad to keep the pad saturated. Coolant from thepad falls into a splash pan where it is collected for return to thestorage tank by gravity flow. The cooler enclosure has a rear facingopening and streamline design to minimize drag and a spoiler device toeliminate a low pressure area that would develop at the rear openingentrance port.

What is claimed and desired to be secured by United States LettersPatent is:

1. A roof top evaporative cooler for a vehicle comprising: a streamlinedhollow enclosure having a forward sloping surface, a rear openingentrance port, and a downwardly opening exit port; said enclosuredesigned to be mounted on the roof of a vehicle; a liquid saturablemedium disposed within said enclosure adjacent the entrance port; fanmeans mounted within the said enclosure for pulling warm air into theenclosure through the entrance port and said saturable medium and forexpelling cooled air from said exit port into said vehicle; andrecirculating means for continuously introducing evaporative coolantliquid into said medium to saturate the same and for recoveringunevaporated liquid coolant from said medium for recirculation.

2. The cooler of claim 1 wherein said enclosure further comprisesdeflector means projecting upwardly of said enclosure, said deflectingmeans being disposed adjacent said forward sloping surface and abovesaid entrance port, whereby warm air passing over said streamlinedenclosure flows downwardly to said entrance port.

3. The cooler of claim 1 wherein the said fan means is disposed betweenthe entrance and exit ports, said exit port being adjacent the forwardedge of said sloping surface so that said fan means cooperates with theinternal surface of said streamline enclosure to direct cooled airdownwardly through said exit port.

4. The evaporative cooler of claim 1 wherein the evaporative coolantliquid is water and the warm air entering the entrance port is cooledand humidified as it passes through the saturated medium and a portionof the liquid vaporizes.

5. The cooler of claim 1 wherein the circulating means comprises:distributing means disposed over said medium for distributing coolantliquid over the upper surface of said medium so that said liquid willseep downwardly therethrough; collecting means disposed under saidmedium for collecting coolant liquid draining from said medium; and pumpmeans connecting said collecting and distributing means forrecirculating said coolant liquid.

6. The cooler of claim 5 wherein said distributing means is a foraminousseepage tube.

7. The cooler of claim 5 wherein said medium is a body of liquidsaturable material permitting free flow of air therethrough.

8. The cooler of claim 7 wherein said body of material is a cloth padmounted in a removable frame.

9. The cooler of claim 7 wherein said body of material is comprised ofporous molded plastic.

10. The cooler of claim 7 wherein said body of material is comprised ofwood fibers retained in a removable open mesh screen.

11. The cooler of claim 5 further comprising a splash plate disposedunder the said medium, said plate collecting the coolant liquid as itdrains from the bottom of said medium; and a storage means communicatingwith said splash plate for receiving the liquid as it collects in saidplate.

12. The storage means of claim 11 including a sealed storage tank havinga filling opening and a liquid level gauge, said tank being disposedwithin said cooler in communication with said splash plate.

13. The storage means of claim 11 comprising a sealed storage tankhaving a filling opening and a liquid level gauge in communication withsaid splash plate for collecting the drainage from said splash plate;said tank being located externally to said cooler and attached to thevehicle.

References Cited UNITED STATES PATENTS 1,539,534 5/1925 Ansell 98-2G1,574,880 3/ 1926 Garland 98-2GX 2,075,389 3/1937 Eubank 62259RC2,977,774 4/1961 Ferris 62-212 3,294,376 12/1966 Eranosian 26191X3,352,353 11/1967 Stevens et al 261A.H.

TIM R. MILES, Primary Examiner US. Cl. X.R.

26196, 97, Dig. 4; 6224l, Dig. 16; 982G

